The problem is to solve the equation $3x^2 - 18 = 0$ using the square root property.

1. Problem Description

The problem is to solve the equation $3x^2 - 18 = 0$ using the square root property.

2. Solution Steps

First, we want to isolate the $x^2$ term. Add 18 to both sides of the equation:

$3x^2 - 18 + 18 = 0 + 18$

$3x^2 = 18$

Next, divide both sides by 3:

$\frac{3x^2}{3} = \frac{18}{3}$

$x^2 = 6$

Now, we can apply the square root property. Take the square root of both sides:

$\sqrt{x^2} = \pm\sqrt{6}$

$x = \pm\sqrt{6}$

So the two solutions are $x = \sqrt{6}$ and $x = -\sqrt{6}$.

3. Final Answer

$\sqrt{6}, -\sqrt{6}$